The North Norfolk Marathon, Half-marathon and Mini-marathon races started in front of Holkham Hall, with the course winding through parkland, the coastal path, and along the quayside at Wells before finishing back at the stately home.

Sun-seekers who had turned out for a Sunday at the seaside cheered and encouraged the runners along the route – but the heat took its toll, with some exhausted competitors needing treatment for dehydration at the finish line.

Organiser Jodie McCallum, from Wells, said the third annual event had been the biggest – and hottest – so far.

“The day went really, really well and we had such a good atmosphere,” she said. “We had a couple of issues because of the weather – there were a couple of people getting dehydrated, but they were treated and everyone is fine.

“A few of the marathon runners converted to half-marathons, and I don’t blame them! Everybody seemed to have a really good day, so we’re very happy.”

Among the faster half-marathon finishers was David Powles, 34, from the Golden Triangle area of Norwich, who said his time of 1hr 44min was slower than last year’s.

He said: “It was just so hot, but it was lovely running along the seafront when you get a great breeze. All along the quay at Wells was really nice. You get a lot of support from people and it makes a massive difference. Just one person clapping makes you go an extra yard faster. Miles nine to 11 are uphill and out in the open so they really kill you – but when you turn round and run round to Holkham Hall it lifts you.”

The event raised an estimated £4,000 for the Wells Harbour Trust and Parkinson’s UK.

As many of the marathon and half-marathon runners reached the finish line, there were also children setting off on 1k, 2.5k and 5k mini-marathon races.